SWCK or Rightmind

I'm planning to send my girl to SWCK for K1 and K2, later ISF for Foundation Year until Grade 12.
Could any parents please kindly help for the following questions? Thank you so much.
1) My husband has suggested another kinder that's Rightmind Kindergarten, there's Mandarin lesson and their Chinese shandard seem to be high; while SWCK doesn't have Mandarin or Chinese lesson. Since SWCK is an English-medium school, is it ok if I'll teach her some simple Chinese characters and speak Chinese with her after school to improve her Chinese standard? Our final target is to get her into ISF successfully, so which one, SWCK or Rightmind should we choose?
2) May I know when can I apply ISF Foundation Year for my girl, one year before or two years before?
3) If my girl failed in the ISF interview, what other school(s) is/are suggested? We want to offer her a bilingual environment (from primary to secondary) with a through-train secondary school to study in, I've heard about RCHK, is it suitable in this case?